CIAM

The gas turbine engine for a «electric» long-range aircraft – the «electric» GTE

Electrification of the gas turbine engine intended for a long-range aircraft is considered. The basic directions of electric energy application on such engine, principles of construction of engine systems with using electric drives for actuation mechanisms, methods of maintenance of reliability, achievable advantages are defined. The list of key technologies is resulted.

Keywords: gas turbine engine, electric engine, automatic control system, fuel system, oil system, electric drive.

Gurevich O.S., Gulienko A.I.

Increasing the reliability of titanium alloys deformation diagrams

Using titanium allow VT6 as an example, the issues of obtaining practically important information from conditional and «true» tensile diagrams are discussed and ways to increase their reliability by taking into account the statistical variation of characteristics are proposed. The numerical-analytical method for determination of the probability characteristics of these parameters as functions of a random variable y and estimating of the minimum values ymin and ef min from the results of sampling tests are described. Comparing the results of testing two groups of samples with a slightly different manufacturing technology, it is shown that this difference most clearly affects the magnitude of the sample relative narrowing y and the true parameters of fracture sf and deformation ef.

Keywords: tensile diagram, titanium allow VT6, statistical variation, probability characteristics, sampling tests.

Shorr B.F., Vilter N.P., Volkov M.E., Khanyan G.S.

Criteria of damage origin in constructions made from composite materials

Meso-model of composite material represented by the two-component medium is described. The techniques of the model parameter determination and the failure criteria of composite material constituents and interface boundary of the unidirectionally reinforced materials are considered. Main resolving equations, which were derived on the base of energy balance, are given. Whole chain of events, which consists of failure initiation in one of the composite material constituents, stress redistribution in the damage vicinity, accumulation and development of damage at load increase and full damage cumulation, bringing to loss of carrying capacity, is shown by researches of strain-stress state of fan blade root model.

Keywords: meso-model, composite material, two-component medium, failure criteria, interface boundary, damage.

Karimbaev T.D.

Prediction of aero engine discs cyclic life based on modeling the steady growth of low cycle fatigue cracks

High-energy-type universal micromechanism of periodic splitting-rupture (PSR) is reviewed. It operates at the front of the fatigue cracks in metallic materials, providing their steady growth and forming T-shaped crack tip and striated microrelief of the fracture surface. Taking into account the PSR micromechanism and asymptotic stress distribution in front of T-shaped crack tip the physically based mathematical model for steady growth of low cycle fatigue cracks is created. On this basis, the techniques for predicting the safe cyclic life of aero engine discs are developed.

Keywords: aero engine discs, low cycle fatigue, fatigue crack, safe cyclic life, survivability diagram, inspection interval.

Tumanov N.V., Lavrentyeva M.A.

Structural optimization of the high-pressure turbine disks

The paper deals with a computer-aided design of disks for high-pressure turbines. The approach is suggested according to which stress-based optimization for the labyrinth and the main disks can be conducted within a single optimization task. For this purpose, the axially symmetric finite-element model was created. This model comprises all structural elements of the disk (except dovetail and blades) with minimal simplification and is almost identical in its quality to standard engineering models.

Keywords: structural optimization, disk, labyrinth disk, turbine.

Salnikov A.V.

Development methodology of compact gas turbine engine demonstrator with rotor in gas bearing basing upon existing structure

The approach to the modernization of existing compact gas turbine engines with rotors in gas foil bearings and the creation of new ones is presented. This approach is based on the combined use of mathematical models and test rigs for gas bearings and rotors supported in gas bearings. The numerical models were used to determine constructions of gas foil bearings. Simulation of dynamics of the compact gas turbine engine demonstrator was performed to confirm the usage of gas foil bearings in rotor’s supports. The life-time tests of isolated bearings in the start-stop mode for the rotor floating up in bearing were conducted. Also, the tests of rotor-simulator supported by gas foil bearing and ball bearing were conducted. The tests for the compact gas turbine engine demonstrator with a gas bearing mounted on turbine (hot) support were carried out.

Keywords: compact gas turbine engine, gas foil bearing, dry engine, demonstrator.

Temis M.Yu., Gavrilov V.V., Egorov A.M.

Influence of ice accretion on turbofan performances in ice crystal conditions

The results of ALF502R Honeywell turbofan testing with ice crystal ingestion at simulated altitude operating conditions (NASA Glenn Research Center) have been used for developing the computational code with the capability to analyze the performance of turbine engine in ice crystal ingestion conditions. The full engine aerothermodynamic performance was modeled specifically for ALF502R engine. The developed code has been verified and showed good matching with test data. Created one-dimensional code indicates the risk of ice accretion which can lead to engine rollback or un-commanded loss of engine thrust and may be used for preliminary evaluation of ice crystal ingestion on turbofan engine performances.

Keywords: turbofan engine, icing, flowing part, mathematical model, engine performance.

Kadzharduzov P.A., Ezrokhi Yu.A.